Water resistant protein materials



Patented Dec. 22, 1953 WATER RESISTANT PROTEIN MATERIALS Hugh J. Hagemeyer, Jr., Kingsport, Tenn., as-

signor to Eastman Kodak Company, Rochester, N. Y., a corporation of New Jersey No Drawing. Application August 24, 1950,

Serial No. 181,320

Claims. (0]..18-54) This invention relates to the preparation of protein materials which are resistant to the effects of water obtained by the acetoacetylation of the proteins with diketene, and then treating the so-formed material with formaldehyde.

It is desirable that materials employed for fibers, foils or filaments have good wet strength and water resistance, a fairly high softening point, and resistance to the effect of water and treatment with aqueous liquids. For instance, in the case of textile materials, resistance to the effects of laundering is desired. In the case of photographic films, .the film base should be resistant to processing baths which are employed in connection therewith. Also it is desirable that material used for these various purposes be resilient, have a good feel, have good dimensional stability, and in the case of textile fibers to be resistant to creasing.

One object of my invention is to prepare protein materials which in the form of filaments, threads, yarns, ribbons and the like have increased laundry and wearing resistance. Another object of my invention is to prepare a protein material, fibers of which have good water resistance, high wet strength, and desirable properties as regards softening point, resiliency, handle, dimensional stability, and crease resistance. A further object of my invention is to prepare a material having these properties bytreating protein with diketene and subjecting the so-treated material to the action of formaldehyde or a formaldehyde-forming material. Other objects, of my invention will appear herein.

The objects of my invention are accomplished by the acetoacetylation of proteins with diketene and subsequently subjecting that material to treatment with formaldehyde or a formaldehyde forming compound, particularly after the material has been formed into threads, filaments, ribbons, foils, films, or the like.

acetoacetylated with'diketene with or without catalyst together with a modified protein composition. Typical proteins which may be used as the starting material in accordance with my invention include zein, casein, gluten, egg albumin aldehydes in the presence of a mildlybasic cata-S lyst to form a cross-linked material. :For in- I have found that proteins contain reactive groups which can be 2 stance, with zein the cross-linking action which occurs is illustrated by the following equation:

Zein Zeln carbon are reactive and any degree of cross-linking desired can be obtained. This process has the considerable advantage over the prior art in that the acetoacetylation can be carried out prior to'the forming of the protein film, foil, or fiber, and in this manner any degradation due to the action of an acetylating mixture on the protein in its final form is avoided. Diketene also has a high reactivity towards basic amino and amide groups and no catalyst is required for the acetoacetylation. Since the diketene provides active points for aldehydic cross-linking of the protein chains, it is possible to prepare a completely acetylated protein composition according to the process of the present invention.

The reaction between the diketene and the protein will take place at room temperature or, if desired, at some increased temperature if thought to be desirable. The reaction occurs just as well without as with a catalyst and, therefore, no catalyst use is necessary. The acetoacetylation of proteins can be carried out in several ways. For instance, the dry protein can be added gradually to the diketene, to a solution of diketene in an inert organic solvent or the diketene can be added to a solution of the protein. Casein and zein in particular can be dissolved or suspended in suitable solvents or combinations thereof and treated with the desired amount of diketene. Because of the greater reactivity of the diketene for the active points of the proteins, i. e., primary amino, basic and primary amide groups, it is possible to carryout the acetoacetylation in the presence of water and/or alcohols without appreciable hydrolysis or esterification. Typical solvent mixtures which are suitable in this step are: water-acetone, Water-alcohol, and alcoholmethylene dichloride. The acetoacetylation proceeds rapidly at ordinary temperatures and, .as a rule, temperatures above about C. are unnecessary in this step. e

Th formaldehydev treatment is best accomplished by treating the acetoacetylated protein" while in the form of films, threads, yarn or the like with an aqueous solution of formaldehyde having a temperature of YO-80 C., which formaldehyde solution contains a very small proportion of some mildly alkaline catalyst such as pyridine, sodium carbonate, dilute alkali, or sodium acetate. The strength of the formaldehyde solution should be at least 3% and not more than 10% is ordinarily suflicient. Although the best results have been obtained from dilute formaldehyde solutions, the described effects can be obtained by treating the filaments or threads by solution of a formaldehyde-forming material in the solution which is to be employed for preparing the ribbons, filaments, foils or films. Also a small proportion of mildly alkaline catalyst would be desired. After the solution has been coated, it is desirable when a formaldehydeforming material is used to heat the threads or ribbons for a short time at a temperature of- 110-130 C. to release the formaldehyde within the material. Some of the formaldehydeforming materials which may be incorporated in dopes or solutions in the: practice of my invention are. para-formaldehyde, hydroxy' methyl nitroparafiins, methylol melamine, or, in fact, any formaldehyde-forming material which can be dissolved in the solution to be spun, coated or extruded and which will release its formaldehyde at a temperature which will not decompose the acetoacetylated protein material. The products thus obtained have a very small moisture absorption and exhibit but minor,- if any, shrinkage by treatment with hot water.

The amount or mildly alkaline catalyst employed in the formaldehyde treatment need only be a trace, such as onthe order of Dill-91%.. Larger proportions of base may be present but do not exhibit any increasedefiecl'h. In addition to the catalystmentioned above, other. catalysts which may be employed for use in the formaldehyde treatment are quinoline, trimethylamine, monoethy'l-amine, alpha or beta picoline, or, for that matter, any basic material of an organicnature. The following illustrates my invention.

Emample I 40 parts ot zein were dissolveda solvent containing; 20 parts of water and 80' parts of acetone; 5 parts of d-iketene were: added and the solution was agitated at. 25 C. for l-2 hours. Skins were coated from the solution, which skins were dried, at room temperature overnight, Strips cut fromthese skins could be drafted. 200%. at 80 C.. in hot.- water. The stretched strips were cured. by treating with 10 formalin. containing 0.1% pyridine at 40'? C. for -30 minutes. The strip after drying; with hot air showed negligible shrinkage in boiling water.

Example II 40 parts of zein were treated with diketene as inv the previous example. The solution was then coated out to. form foils, which foils were treated with a 3% formalin solution containing 0.1% pyridine as a catalyst at C. for 5 minutes. After washingand drying; the.' foils werecut into.- strips and drafted to 300% of the: original length. The final cure was obtained by treating with 1.0% formalin containing 0.1 sodium hydroxide at ell-50 C. for 20 minutes. These foils were dried in warm dry air and; upon-treatment with boiling water showed not; more than 3-4% shrinkage.

Example III 40 parts of zein wer dissolved in 30' parts of diketene and 70 parts of acetone. Solution was obtained by beginning the addition of the zein i tihility for the untreated zein.

Example IV Zein fibers were obtained by dry spinning a any, solution of zein in a :50 mixture of methanol-methylene dichloride. The fibers formed were partially cured by treating with aqueous formaldehyde solution and stretching the same. These partially cured zein fibers wer then acetoacetylated by treating with a 10% solution of diketene in carbon tetrachloride. A final. cure was obtained by treating thefiberswith a. 10 formaldehyde solution using 0.1% sodium hydroxide as a catalyst at C. for fifteen minutes.

Example V 40 parts of casein were dissolved in 50 parts of diketene to which as solution was obtained 50' parts of acetone were slowly added. Foils were coated from this solution and dried at 25 C. overnight. The modified casein was immersed in a 10% formalin solution containing 0.1% pyridine and. heated at 50-50" C, The casein foils 50 treated were cross-linked by the formaldehyde and exhibited a low susceptibility to water.

ll'claim:

1'. A process for the preparation of attenuated protein material which comprises forming a solution of a protein, aceto acetylating the protein while in solution, with diketene whereby --CO-CHz-CO- groupings are obtained therein, imparting an attenuated form to the aceto' acetyl'ated protein and treating the so formed protein derivative with an aqueous sclution of formaldehyde of 3-100% concentration and a mildly alkaline catalyst which solution has a temperature of ill- 6;, whereby cross linking is induced in the attenuated product as evidenced by no appreciable shrinkage thereof upon treatment of the same with hot water.

2'. A process for the preparation of attenuated zein material which comprises forming a solution of zein, aceto acetylating the zein while in solution with diketene whereby -COCH2CO groupings are obtained therein, imparting an attenuated form to the aceto acetylated zein and treating the same with an aqueous solution of formaldehyde of 3-10 concentration and a mildly alkaline catalyst which solution has a temperature of 40-80" 0., whereby cross linking is induced in the attenuated product as evidenced by no appreciable shrinkage thereof upon treatment of the same with hot water.

3 A process for the preparation of attenuated casein material which comprises forming a solutionof casein, aceto acetylating the casein while in solution with diketene whereby groupings are obtained therein, imparting an attenuated form to the aceto acetylated casein and treating the same with an aqueous solution of formaldehyde of 349% concentration and a mildly alkaline catalyst which solution has a temperature of 40-80" C. whereby cross linking is induced groupings are obtained therein, imparting an attenuated form to the aceto acetylated protein and treating the same with an aqueous solution of formaldehyde of 3-10% concentration and pyridine which solution has a temperature within the range 40-80" C. whereby cross linking is induced in the attenuated product as evidenced by no appreciable shrinkage thereof upon treatment of the same with hot water.

5. A process for preparing protein filaments which comprises forming a solution of zein, aceto acetylating the zein while in solution with diketene whereby -COCH2CO groupings are imparted to the zein, forming the aceto a'cetylated zein into filaments and treating the filaments with an aqueous solution of formaldehyde of 13-10% concentration and a mildly alkaline catalyst which solution has a temperature of 70-80 0. whereby cross linking is induced in the attenuated product as evidenced by no appreciable shrinkage thereof upon treatment of the same with hot water.

HUGH J. HAGEMEY ER, JR.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 965,137 Goldsmith July 19, 1910 2,171,241 Johnson Aug. 29, 1939 2,236,768 Veatch Apr. 1, 1941 2,342,634 Atwood Feb. 29, 1944 2,525,792 Gordon et a1. Oct. 17, 1950 FOREIGN PATENTS Number Country Date 536,841 Great Britain May 29, 1941 593,928 Great Britain Oct. 29, 1947 OTHER REFERENCES Silk Journal & Rayon World, July 1947, pages 46, 51. Protein Rayons. 

1. A PROCESS FOR THE PREPARATION OF ATTENUATED PROTEIN MATERIAL WHICH COMPRISES FORMING A SOLUTION OF A PROTEIN, ACETO ACETYLATING THE PROTEIN WHILE IN SOLUTION, WITH DIKETENE WHEREBY -CO-CH2-CO-GROUPINGS ARE OBTAINED THEREIN, IMPARTING AN ATTENUATED FORM TO THE ACETO ACETYLATED PROTEIN AND TREATING THE SO FORMED PROTEIN DERIVATIVE WITH AN AQUEOUS SOLUTION OF FORMALDEHYDE OF 3-100* CONCENTRATION AND A MILDLY ALKALINE CATALYST WHICH SOLUTION HAS A TEMPERATURE OF 40-80* C., WHEREBY CROSS LINKING IS INDUCED IN THE ATTENUATED PRODUCT AS EVIDENCED BY NO APPRECIABLE SHRINKAGE THEREOF UPON TREATMENT OF THE SAME WITH HOT WATER. 